We have developed a VB app that monitors user's phone lines and retrieves the caller id value and the called id value depending on if the user is making an incoming or outgoing call.

The application works fine on a single telephone line. However, we have a number of users who's phones are attached to the same phone line.

The application works for the first couple of calls but after that it stops working. The application is still running, but it is not doing anything. I have used the outputdebugstring API to output data to the debug window but after the first few calls no information is being sent. This tells me that the application is not receiving any TAPI information.

Does anyone have any ideas as to the cause of the problem?

I know it is application based because we have a number of different TAPI servers and each site is having the same problem.

I had a feeling that it might have been because the call is not being dropped. However, from my reading of TAPI all incoming calls are dropped automatically by the TAPI server.